There is an ever increasing need to be able to authenticate items, for example electronic devices, official documents, credit cards, mobile communication devices etc. The need for authentication may rise from different interests, such as detecting forgeries and copies or control of usage of items.
There is a variety of item authentication technologies available for use depending on the item. One of these techniques is the Physical Unclonable Function (PUF) that is embodied in the physical structure of the item. If a physical stimulus is applied to the physical unclonable function it reacts in an unpredictable and repeatable way to that stimulus depending on the structure.
Previous physical unclonable functions have been often found complicated to implement or they have presented security risks, such as offering a backdoor to the device being authenticated. It is an object of the present invention to mitigate the problems of PUF-authentication.